Rapid economic development in many countries has resulted in increased environmental pollution. In particular, indoor environmental pollution caused by the use of various chemicals associated with the production of items such as decorative materials, furniture, tobacco, and household appliances is of growing concern. Many of the appliances, furnishings, and painted surfaces found in new home constructions release volatile organic compounds (VOCs). VOCs include hydrocarbons, carbonyl compounds, organic acids, organic peroxides, organic sulfur compounds, organic halides, and the like. VOCs can also participate in photochemical reaction with nitrogen oxides and sulfides of the atmosphere upon exposure to light and form highly toxic photochemical smog.
Many VOCs have been found to be carcinogenic or suspected carcinogens (such as formaldehyde, benzene, tetrachloroethylene, trichloroethane, trichlorethylene, and the like). Major emission sources of indoor air VOCs include wall coatings (e.g., paint and wallpaper) and oil paints and varnishes for furniture. However, recently, houses have become more and more airtight and, accordingly. VOCs can result in more serious health issues because they cannot rapidly escape the indoor environment.
There are a variety of commercial air fresheners and deodorizers that can temporarily mask the odor of some VOCs, but they do not fundamentally eliminate harmful sources of pollution, and can themselves act as new secondary pollution sources. Of the many VOC pollutants, there is widespread concern regarding the effective control of formaldehyde in paints and adhesives. Some commercially available products for formaldehyde removal are available; however, there is no effective product for removal of VOCs in general. Most commercially available products must be replaced when saturated, since there is no way for the consumer to change the adsorptive material therein.